1. Field of the Invention
The present invention relates to electrical connector technology and more particularly, to an electrical power connector fabrication method, which employs a cold drawing procedure to draw a metal round rod into a conducting contact bar, and then stamping and cutting techniques to make metal contacts, and then an injection molding technique to mold electrical housings on metal contacts so that a large number of electrical power connectors can be formed rapidly at a time, saving the cost.
2. Description of the Related Art
Power sockets are widely used in electric and electronic devices, such as portable audio, audio and video players (CD, VCD, DVD players), computer, notebook computer, mobile phone and other information products for connection to a city power outlet for power input so that the electric and electronic devices can obtain the necessary working power supply and can be operated by a user.
A power socket has at least one metal contact that can be made in a solid or hollow form. A hollow metal contact, as shown in FIG. 18, is made by: using a stamping technique to stamp a metal sheet material, for example, copper sheet material into a predetermined shape, and then bending the shaped copper sheet material into a cylindrical configuration having a rounded contact portion A at its one end and a flat mounting portion B at its other end. Because this design of hollow metal contact is made by curving a shaped copper sheet material into a cylindrical configuration without riveting, the applied force must be properly controlled when curving the shaped copper sheet material. If the applied force is excessively high or insufficient, the two opposite side edges of the shaped copper sheet material may not be positively and accurately abutted against each other after formation of the metal contact, lowering the product yield rate. Further, a hollow metal contact has a relatively lower structural strength, and can easily be deformed or damaged upon connection between the power socket and a mating electrical connector. Further, when curving a shaped copper sheet material into a cylindrical configuration, a seam line will be left at the front side of the hollow metal contact, affecting the sense of beauty of the outer appearance of the hollow metal contact.
Further, a power socket using solid contacts is known, as shown in FIG. 19, comprising an electrically insulative housing C, and a first solid contact D and a second solid contact E mounted in the electrically insulative housing C. The first solid contact D has a locating flange D1 extending around the periphery thereof and positioned in a front side of a back wall of the electrically insulative housing C and a rear mounting end D2 extended out of the back wall of the electrically insulative housing C. The second solid contact E is riveted to the rear mounting end D2 of the first solid contact D. Further, the first solid contact D is made of a metal material using a milling technique. However, because the locating flange D1 has a relatively larger outer diameter than the first solid contact D, the metal material used for making the first solid contact pin D must have a diameter not less than the outer diameter of the locating flange D1. Thus, about 40% of the metal material is wasted, increasing the material cost. Moreover, further waste recycling is necessary to recycle waste metal material. Further, because the first solid contact D and the second solid contact E are riveted together, they may be loosened from each other after a long use. If the first solid contact D and the second solid contact E are loosened, a large electrical resistance may be produced during transmission of electricity, leading to the problems of high temperature, poor contact, electric shock or connector dropping and severely affecting application safety.
Therefore, the fabrication of electrical power connectors using either solid or hollow metal contacts according to the prior art methods has the drawbacks of low metal contact structural strength, low product yield rate, large amount of waste material, requirement of an extra waste material recycling treatment, and high manufacturing cost.
Therefore, it is desirable to provide a method for making metal contacts and electrical power connectors that eliminates the aforesaid problems.